Our previous studies demonstrated that the sexually dimorphic pattern of hypertension in the spontaneously hypertensive rat is androgen dependent. Gonadectomy retards the development of hypertension in young males, but not in females, and administration of testosterone propionate to gonadectomized spontaneously hypertensive rats of both sexes confers a male pattern of ...

The antihypertensive effect of calcium antagonists is altered little by high salt intake or concomitant diuretic treatment. We therefore investigated whether modest changes in the salt balance might alter the acute response of the renin-angiotensin system to the calcium antagonist isradipine in conscious rabbits. Mongrel rabbits with indwelling arterial and ...

A series of renin inhibitors having alpha-heteroatom amino acids as P2 substitutions has been prepared. Examples where the heteroatom is oxygen, sulfur, or nitrogen are described. Many of the compounds exhibit subnanomolar potency when tested in vitro against monkey renin. When selected compounds were tested orally in conscious, salt-depleted, normotensive, ...

We examined the relationship between acute reductions in renal perfusion pressure, as approximated by femoral arterial blood pressure, and plasma renin activity in the uninephrectomized fetal lamb. Renal perfusion pressure was reduced and maintained at a constant value by controlled partial occlusion of the aorta above the renal artery. After ...

Correlation between increased cranial and peripheral norepinephrines and increased cranial to systemic renin ratio has been observed in a small number of patients with postcarotid endarterectomy hypertension. In an effort to confirm these findings, we studied cranial and peripheral levels of catecholamines and peripheral renin activity in 120 consecutive carotid ...

Pulmonary artery pressure (PAP) increased significantly in rats after hypobaric hypoxic exposure for 15 days (CH15) (P less than 0.001) and was maintained at the same level after prolonged hypoxic exposure for 40 days (CH40). There were no significant changes in carotid systolic and diastolic blood pressure in CH15 and ...

High renin hypertension is usually accompanied by impairment of the baroreceptor reflexes. This feature has been mostly ascribed to overactivity of the renin-angiotensin system. However, renal nerves could also modulate the baroreceptor reflexes. In the present experiments, the effect of renal denervation on the depressed baroreceptor reflexes was studied in ...

We describe methods for using ameroid constrictors to develop renin-dependent hypertension in dogs. A vascular-access-port was implanted in each dog and mean arterial blood pressure was monitored. Via a small flank incision, an ameroid constrictor was placed on the left renal artery and mean arterial blood pressure, plasma renin activity, ...

We measured blood pressure, platelet cytosolic calcium concentration ([Ca2+]i) and vasoactive hormones in 20 anuric normotensive patients on chronic hemodialysis (HD) to clarify the role of cytosolic calcium in regulation of blood pressure. All measurements were performed at the end of HD (post-HD) and at the beginning of the next ...

Control of blood pressure usually has not, by itself, affected the incidence of heart attack in hypertensive patients. This suggests a need for cause-specific therapy targeted against mechanisms that engage the risks of myocardial infarction. Study of the renin system, the ongoing, long-term servo-control over blood pressure and electrolyte homeostasis ...

The protease inhibitor aprotinin was given a) in experimental septic shock, and b) in patients with hepatic cirrhosis and ascites, since in both conditions, activation of the plasma kallikrein-kinin system is associated with pathological systemic vasodilatation, which may trigger reflex neuroendocrine activation and renal solute retention. Given early in experimental ...

Factors that can influence cardiovascular growth are becoming increasingly important for our understanding of such complex diseases as cardiac hypertrophy, coronary artery disease, atherosclerosis, and hypertension. Several proto-oncogenes were found to be involved in the regulation of abnormal cell growth in cardiovascular disease. It is also evident that some peptide ...

We examined the usefulness of aspirin DL-lysine for prediction of the outcome of renal artery angioplasty in renovascular hypertension. The study was carried out in eight hypertensive patients with unilateral renal artery stenosis: six were free from azotemia and two had slight azotemia. Before and 30 min after an intravenous ...

To determine the biochemical and hemodynamic responses to aortic ligation, and to assess the survival rate after the induction of hypertension, 90 normotensive rats were subjected to surgical constriction of the abdominal aorta. Mortality, left ventricular hemodynamics, myocardial biochemical assays, and plasma renin assays were determined 1 week, 1 month, ...

In humans, blockade of the renin-angiotensin system with angiotensin converting-enzyme inhibitors (ANG CEI) prevents the rise in blood pressure associated with the administration of recombinant human erythropoietin (rhEPO). This study was conducted to determine whether rhEPO elevates blood pressure in normal Wistar rats and whether the renin-ANG system is affected. ...

As there is a 10% risk of hypertension developing in children with reflux nephropathy and the renin-angiotensin system has been implicated in its aetiology, a long term prospective study has been undertaken to explore the relationship between plasma renin activity (PRA) and blood pressure in such patients. In 1978, of ...

Arterial hypertension is sustained by either of two long-term mechanisms of arteriolar vasoconstriction or by an inappropriate reaction between them. One mechanism is renin-mediated, the other is related to antecedent renal sodium retention. The plasma renin value directly reflects the presence and degree of renin-mediated vasoconstriction, and, inversely, defines the ...

It is known that the renin angiotension system as it is usually understood is not the mediator of experimental one-kidney, one-clip (1K,1C) hypertension in animals. There is also ample evidence that the blood pressure of dogs and rabbits with this form of hypertension can be lowered by immunization with hog ...

The renin-angiotensin system (RAS) is an important modulator of blood pressure and fluid balance. The clinical success of angiotensin converting enzyme inhibitors (ACEIs) in the treatment of hypertension has stimulated the search for antagonists of renin. Because renin is highly specific for its substrate, angiotensinogen, renin inhibitors may emerge as ...

This paper attempts to define the theory and practice of a modern approach to the initial workup of the patient with hypertension. The process includes a complete general medical evaluation along with special measures to enable the fullest characterization and clinical differentiation of the disease. The initial workup aims to ...

Renin-like activity can be demonstrated in arterial extracts from normal rats and from rats with Goldblatt hypertension. We have found no evidence, however, for elevated arterial renin levels in relation to plasma renin activity. Studies of the reversal of renovascular hypertension indicate that the fall in blood pressure produced by ...

Vasoactive hormones acting as endocrine, neuroendocrine, or local hormonal systems (intracrine, autocrine, and paracrine) are an important component of the many factors that regulate blood pressure. Hypertension may be the result of an alteration in the balance between vasodepressor and vasopressor hormonal systems. Changes in this balance could be due ...

Although many in vitro and animal studies indicate the existence of a local renin--angiotensin system, data regarding its physiological role are quite controversial, and moreover, evidence suggesting inactive and active renin release from vascular tissue in vivo is lacking both in animal and humans. The aim of our study was ...

Responses of renin release and blood pressure to aspirin DL-lysine (ASP) were examined to find out if the responses could help in the differentiation between unilateral renovascular hypertension (RVH) and hyperreninemic essential hypertension (EHT). The two studies involved ten patients with unilateral RVH, eight with hyperreninemic EHT, and five with ...

The aim of the present study was to look for possible additive or synergistic effects of the combined oral administration of a single dose of an angiotensin converting enzyme (ACE) inhibitor, benazepril (10 mg) (B), and a long-acting vasodilator, cadralazine (5 mg) (C), on blood pressure, arterial parameters, and active ...

Pharmacological blockade of the renin-angiotensin converting enzyme reportedly alters the heart rate (HR) power spectrum in conscious dogs, suggesting that these hormones contribute to the short-term regulation of arterial blood pressure. We tested this possibility using four independent procedures. First, HR power spectrum was determined in seven awake dogs before ...

A series of renin inhibitors containing ester side chains at the P2 subsite are potent inhibitors of primate renin. Derivatives containing the diol isostere (ACDMH) at P1-P1' were the most potent inhibitors. Moderate selectivity for renin was observed relative to the closely related aspartic proteinase cathepsin D. The prototype compound, ...

The goal of the present study was to characterize the new renin inhibitor Ro 42-5892 in vitro and in vivo. In vitro, Ro 42-5892 inhibited purified human renin and human plasma renin specifically with an IC50 of 0.7 nM and 0.8 nM, respectively. In vivo, Ro 42-5892 reduced mean arterial ...

The purpose of this study was to examine the relationship between the variability of awake ambulatory blood pressure and the level of plasma renin activity (PRA) in age-matched samples of untreated hypertensive white men. The ambulatory pressures of 376 men (145 under 45 years of age, 231 over 45) were ...

To investigate the involvement of prostacyclin and the sympathetic nervous system in cardiovascular responses to 1-desamino-8-D-arginine vasopressin (DDAVP), a selective V2-receptor agonist, in normal subjects, DDAVP (0.4 micrograms/kg) was infused with or without indomethacin, a cyclooxygenase inhibitor, or propranolol, a beta-adrenoceptor antagonist. A decrease in blood pressure and increases in ...

Hypertension accompanies chronic exposure of rats to cold (5-6 degrees C). Systolic, diastolic, and mean blood pressures become elevated, and hypertrophy of the heart occurs. A previous study from this laboratory suggested that the renin-angiotensin system may play a role. The present study was carried out to assess this further. ...

Electrical stimulation of the isolated rat mesenteric vascular bed resulted in a frequency-dependent pressor response, which could be potentiated by increasing concentrations of renin substrate (synthetic tetradecapeptide). This potentiating effect appeared to be mediated by tissue conversion of renin substrate to angiotensin II because the response 1) could be mimicked ...

To elucidate the effect of natriuretic and antinatriuretic factors on the excretion of an intravenous sodium load, we observed the natriuretic responses of 12 patients with essential hypertension (EHT) and 7 age- and sex-matched normotensive (NT) subjects following the intravenous administration of 1500 mL of normal saline over a 3 ...

Both respiratory and metabolic acidemia stimulate the secretion of adrenocorticotropic hormone (ACTH), vasopressin, and renin. The present study was designed to test the blood pressure, heart rate, and endocrine responses of conscious sheep to low-rate infusions of H+. We infused HCl and lactic acid at a rate of 500 mueq/min ...

A renin-sodium nomogram for normotensive children and adolescents was developed at our institution. The ambulatory blood pressure patterns of subjects classified by the nomogram were then compared. A biracial sample of 159 children and adolescents were classified as having a low, intermediate, or high renin-sodium profile based on the relationship ...

The pathogenesis of hypertension is associated with a remodeling of vascular structure. Folkow has postulated that the decreased luminal area and thickened medial layer in hypertensive vessels enhance the vasoconstrictive response to vasoactive agents. It is hypothesized that this increase in vascular reactivity may serve to perpetuate hypertension. These same ...

Previous efforts to block the renin-angiotensin system in patients with chronic congestive heart failure (CHF) have focused on 2 distal sites in the system, the angiotensin-converting enzyme and the angiotensin II receptor. Recent work, however, has led to the development of agents that directly inhibit renin, the proximal step in ...